1. Technical Field
This application is generally directed to improving the performance in a multi-server environment. More specifically, this application is directed to improving the workload management of EJBs hosted in a clustered J2EE environment.
2. Description of Related Art
An Internet provider of information and services must contend with numerous problems. They must provide services to clients while simultaneously protecting themselves from inadvertent or malicious intrusions into their databases. They must often provide a guaranteed, specific level of quality, e.g., response time, while at the same time keeping overhead low so that a profit can be made. Management programs can monitor and control processes within the computer system to optimize the usage of components and capabilities in a constantly changing environment. Providing online information is an evolving field and not all areas are optimized. For example, in systems that use multiple servers, it is important to spread the load among the servers so that the work can be optimally processed, with no server sitting idle while other servers are busy. Load balancing is a known method of balancing the workload among a plurality of servers. Yet all servers are not created equal. To this end, each server can have a weighting factor, so that a faster server can be given more work than a slower server.
Choosing the correct approach in determining these server weights is a critical decision, because inaccurate weights can adversely affect the performance of the load balancing. Past approaches to determining these server weights have utilized a “pinging” approach to measure server response, an indicia of server load. One limitation of “pinging” approaches to load balancing is that they generate additional traffic on the monitored application, and that they represent synthetic user performance not real-user performance. Another approach is listening at the packet and port level at a centralized server to measure server response for each request. While this approach works well for web traffic that uses the HyperText Transfer Protocol (HTTP), Enterprise Java Beans (EJBs) utilize Internet Inter-ORB Protocol (IIOP) requests to service business transactions. IIOP requests have some critical differences that limit the effectiveness of these traditional approaches.
When hosted within a clustered Java 2 Platform Enterprise Edition (J2EE) business environment, clients of EJBs issue a Java Naming and Directory Interface (JNDI) lookup directly to their local configuration manager. The configuration manager, based on the server weights for each EJB container, determines which EJB reference to return to the client. Once the initial request to the EJB is gained, EJBs use transient ports to satisfy their actual business logic. Since these ports are transient, it makes the port-listening approach to load balancing difficult.
Furthermore, rather than treat the response times of all EJBs of a particular server equivalently, as is done by the “pinging” method, it would be even more beneficial to be able to narrow the focus of the response times measured to the performance of particular business-critical EJBs or the response times that particular users are receiving. In the HTTP load-balancing arena, cookies are typically used to identify and prioritize important users during load balancing. In the EJB space, a solution to identify and prioritize the experience of particular EJB users is needed.
Therefore, it would be desirable for the system to be able to change the weightings for a plurality of servers to dynamically manage the EJB workload.